Date of Award

2024

Degree Name

Biomedical Research

College

Joan C. Edwards School of Medicine

Type of Degree

Ph.D.

Document Type

Dissertation

First Advisor

Dr. Monica Valentovic, Committee Chairperson

Second Advisor

Dr. Gary Rankin

Third Advisor

Dr. Travis Salisbury

Fourth Advisor

Dr. Brandon Henderson

Fifth Advisor

Dr. Piyali Dasgupta

Abstract

The use of electronic nicotine delivery systems (ENDS) has become popular in recent years as an alternative to traditional cigarettes. These devices heat and subsequently vaporize e-liquids for inhalation by the user, which allows for the delivery of ingredients such as flavorings, nicotine, and solvents through the vapor. Flavorings used in e-liquids are “generally recognized as safe” (GRAS) for consumption by the Food and Drug Administration (FDA), however there are currently no recommendations on safety regarding the inhalation of flavoring agents. While research characterizing effects of e-liquids and their flavorings is abundant in lung and respiratory tract models, few studies examine the effects of e-liquids systemically. The kidney is a highly dynamic organ that receives a substantial amount of blood flow from cardiac output, and it is responsible for filtering substances such as e-liquids after they are inhaled and passed into the bloodstream. The purpose of this study was to investigate and determine cellular stress responses to the popular e-liquid flavorings cinnamaldehyde (CIN), vanillin (VAN), and ethyl vanillin (ETH VAN) in the human proximal tubule (HK-2) epithelial cell model. HK-2 cells were exposed to 0-100 µM CIN or 0-1000 µM VAN/ETH VAN for 24 or 48 h and various cellular stress responses were tested. Mitochondrial and glycolytic function were assessed using an Agilent Seahorse XFp assay machine. Total number of cells for Seahorse assays was determined by using CyQuant Direct Cell Proliferation assays and results were normalized to number of cells. Cell and mitochondrial viability were examined by using trypan blue exclusion and MTT assays. Additionally, mitochondrial oxidative phosphorylation complex (OXPHOS) expression was probed using western blot analysis. Expression of autophagy, mitophagy, endoplasmic reticulum, and oxidative stress markers were also probed using western blot analysis. Western blot results were normalized to total protein concentration. The results obtained for this dissertation show flavor-specific cellular stress responses after 24 and 48 h exposure to e-liquid flavorings in HK-2 cells. The data here are the first to characterize such effects in a renal model, and therefore support further investigation into the systemic health risks associated with the use of ENDS devices.

Subject(s)

Vanillin.

Epithelial cells.

Electronic cigarettes.

Apoptosis.

Flavor.

Mitochondria.

Kidneys.

Download

Share

COinS